Tom Brady capped a Week 1 that had 14 300-yard passers, and forced defenses league-wide to alter their approach.

This has been a season of adjustments. It started with teams learning on the fly during a condensed training camp after the lockout. Then offenses came out more ready and preformed at a record-setting pace to open the season. Now the defenses are starting to figure things out.

Week 1 produced a record 14 300-yard passers. After an average of 10 in Weeks 2 through 4, that number has steadily dropped. Over the past three weeks, there have been a total of 15 300-yard passers. Obviously, the bye weeks play a part in the decline, but there's a trend here. There was an average of 47 points scored per game in Week 1. That number fell as low as 40.2 in Week 6 and 41.6 last week.

Defenses that initially had to play catch-up have made the necessary adjustments. Here are four reasons why offensive numbers have fallen off pace.

300-yard passing games by week in 2011

Week

300-yard passers

Games

1

14

16

2

9

16

3

11

16

4

10

16

5

6

13

6

6

13

7

3

13

1. Continuing education

In training camp, there were two trains of thought for installing defensive coverages and pressures -- each with its shortcomings.

Some teams put them in one at a time, which reduced the number of coverages that could be taught with only a few weeks to learn. While that style allowed for a deeper understanding of the limited playbook, it restricted the number of looks a defense could throw at an opposing offense.

Others installed coverages quickly. The result: A wider range to call upon, but the speed at which things were installed left players uncertain of their responsibilities once the season started.

Offenses took advantage of the limitations of both situations. As time has gone on, defenses have had an opportunity to install additional coverages and pressures and refine what they are doing. That, along with five or six weeks of game tape from this season, has allowed defenses to close the gap.

It takes time to play defense as a group, especially when you're talking about learning anywhere from 30 to 50 coverages. For example, a secondary is made up of at least four players that must communicate and understand each other's roles to succeed. Conversely, a receiver's primary role is to run his assigned route -- a solitary endeavor.

Bengals defensive coordinator Mike Zimmer knew he was in for a unique challenge without any offseason practices with his unit. With that, Zimmer reached out to former head coaches Bill Parcells and Chuck Fairbanks during the lockout to see how they did things when they didn't have time with their players in the offseason. Their advice was to keep it simple.

It's worked for the Bengals, who are 4-2 in large part because of their defense, but they have only faced one top 10 offense (Buffalo). Other teams took longer to figure out what offenses were doing, which brings us to ...

2. Adjusting to new tricks

Offenses have leaned on shotgun more on first and second down this season. Screens and draws are also being called out of the formation. The screen is being used instead of the run game in many cases because it's a low-risk play but has more big-gain potential.

As defenses have to play together, the same can be said for an offensive line. The limited training camp time impacted teams to the point where we've seen more slide protection -- a style often used in college to cover up for a lack of talent -- that can buy extra time in the pocket.

These nuances took time for defensive coordinators to break down. Defenses are now more prepared for the blocking and shotgun variations and have better understanding of how to slow down offenses.

3. Wear and tear on QBs

In talking with several defensive coordinators around the league, there's a belief that quarterbacks are getting hit a lot more than ever before.

Being sacked has obvious implications, but your quarterback taking shots over the course of a series, game and season is often overlooked. Aside from the injury implications, it's equivalent to a boxer taking body blows. You can only be so sharp in the fourth quarter if you've taken a beating throughout the game.

Eli Manning, Mark Sanchez, Matt Ryan and Tony Romo are all on pace to have a more sacks and hits this season. Manning, for example, was sacked 16 times all of last season, but already has been taken down 14 times in six games.

An offshoot of the abuse is more interceptions. Mistakes happen when a quarterback gets happy feet and is consistently hit. Look no further than Philip Rivers, who already has nine picks compared to 13 in 2010, as proof of that theory.

4. Defenses taking calculated risks

While blitzing is up, defenses aren't taking the same risks that they have in the past. As odd as that combination sounds, teams are relying more on shell coverage to minimize big plays when they bring pressure. Shell coverage most easily can be described as a more aggressive form of the prevent defense.

Being able to come after the quarterback without worrying about getting beat deep gives defensive coordinators the freedom to bring pressure more often. They improve their chances for a big play without doing the same for the opposing offense.

***

While everyone loves to see points put on the board, the great thing is that as scoring has dropped games have remained compelling. There have been 54 games decided by seven points or less this season, which is the same number we had at this point a year ago.

As we approach midseason, it's time for offenses to now adjust to what defenses have tweaked. The cycle never ends, and it's what one of the things that makes this game so great.

NFL odysseys

» DeMarco Murray's 91-yard touchdown run is the second-longest ever by a player on his first touchdown. Surely everyone remembers Lions RB Bob Hoernschemeyer peeling off a 96-yarder in 1950, right?

» LaDainian Tomlinson became the fourth running back in league history to catch 600 passes with three receptions against the Chargers. He's now at 602.

» Ronde Barber started his 190th concecutive game for the Bucs, which is the most ever for a cornerback. In the loss to the Bears, Barber recorded his 27th career sack, also a record for the position.

» The Saints beat the Colts, 62-7. The previous seven teams to score 60-plus points in a game went 1-5 the next week. One team accomplished the feat in the regular-season finale.

» There were 10 field goal attempts of 50 yards or longer in Week 7, nine were converted.

College watch

Marvin McNutt of Iowa had six catches for 184 yards and three touchdowns in a blowout of Indiana. He is former quarterback who reminds me some of Jordy Nelson. McNutt has the size and speed needed for the position at 6-foot-2½ and 215 pounds with 4.5-second speed in the 40-yard dash.

McNutt came into the season as a third-day pick, but has played well enough to be considered a low second- or high third-round choice. He's not necessarily going to be No. 1 receiver in the NFL because he has good speed, not great.

In some ways, McNutt reminds me of Michael Irvin. Both had about the same speed. I took Irvin in the first round, but not sure he would go there today because people focus on that 40 time so much more.

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The winner of this game will be in first place in the AFC West. That's pretty amazing when you consider Kansas City lost its first three games, giving up 109 points in that span.

The Chiefs were a team that came out of training camp sluggish and then had to overcome a rash of injuries. However, things have settled down and they've given up 41 points over the past three games. That's without star safety Eric Berry, who is done for the year.

Chargers running back Ryan Mathews has had a stellar start to the season after struggling as a rookie. He always had good running ability, but is much improved as a receiver. Chiefs linebacker Derrick Johnson, who leads the team in tackles, will be charged with trying to slow Mathews down. Johnson is playing at a Pro Bowl level and is good against the run and playing in space.

Chargers left tackle Marcus McNeill must find a way to handle Chiefs pass rusher Tamba Hali. Philip Rivers has struggled and needs protection to get things going again. McNeill is very good and has the long arms to get into Hali, who relies on quickness and competitiveness to win.

Kansas City seems to have momentum on its side, and I think it continues with another win this week.